1. Field of the Invention
This invention relates generally to the storage and use of two or more components to be mixed together, and more particularly to the storage and mixing of precise amounts of two or more components to be mixed together.
2. Description of the Prior Art
Polymeric materials such as epoxies, polyurethanes, and the like, are widely used in many industries. These materials, which are used as adhesives, encapsulants, fillers, sealants, protective coatings, and in many other ways, generally are available in a large range of physical, chemical, electrical, and thermal properties which can be tailored to an intended usage.
The aforementioned materials normally comprise two or more components that cause a chemical reaction to take place once they are mixed. Thus, the components usually are not mixed together until the resulting mixture is ready to be used, inasmuch as the aforementioned reaction, referred to as polymerization, changes the mixture irreversibly in a comparatively short time. The time between the mixing activity and a final "curing" of the mixture must be used for applying the material as intended. Basically, the mixed components are transformed into a solid by a solidification process which can be as short as a few seconds or as long as many hours after the initial mixing of the components. For this reason, such materials are sold, packaged, and stored in an unmixed state.
It is possible to slow down, and even stop the aforementioned solidification process by lowering the temperature of the mixed components. This requires the use of such substances as dry ice, refrigeration equipment, cryogenic materials, and the like, which are expensive and/or difficult to use. As a result, this manner of slowing the solidification process is not particularly popular.
As an alternative to slowing the mixing process by lowering the temperature of the components, it is commonplace to refrain from mixing the components until they are ready to be applied in some manner. At this time, proper amounts of each component are measured in some manner and mixed together. Often this entails holding a pair of tubes, one in each hand, and squeezing estimated amounts of each of the components into an area to be bonded, foamed, and the like.
Various devices have been proposed for facilitating the mixing action. For example, it is known to use specially constructed dual-compartment plastic tubes, separated internally by an external clamp. When the clamp is removed from the tube, the chemical components within the tube can be manually mixed together by a kneading action on the outside of the otherwise sealed tube. It also is known to use dual syringes for metering equal amounts of the, for example, two substances being employed. This arrangement, usually employed for only small amounts as needed, requires that the metered substances subsequently be manually mixed together.
Alternatively, dual syringe-type packages are known which have a plastic static blender in the form of crisscrossing screw threads attached to an output end of the device. When the syringes are evacuated through the static blender, the, for example, two components cross fluid paths perhaps as many as thirty times, thus effecting a mixing action. Among problems encountered with this known system are the high cost of the package itself, the less than good mixing obtained, and the loss of the material that inherently remains within the static blender.
In large scale manufacturing situations, there is known automated metering and mixing machines. A principal disadvantage of these machines is that they are suitable only for continuous operation situations, and further must be purged and cleaned at the end of each manufacturing run.
Further, the dental professions commonly use a dental amalgam packaged in a small packet, or capsule, of multiple compartments which are joined together by shaking or squeezing the packet. Typically, these constructions include a small container in the form of a capsule which holds a powdered alloy filling dosage and a rupturable chamber holding liquid mercury. See, for example, U.S. Pat. Nos. 3,841,467, issued October 15, 1974, to D. A. Hansen, and 4,306,651, issued Dec. 22, 1981, to E. Muhlbau. A basic disadvantage with these capsule constructions, however, is that they are suitable only for minute quantities of substances to be mixed. Often, the quantities to be mixed are such as to make such hand-shaking, or vibrating, impractical. Further, the substance within the capsule should be a heavy material, such as mercury.
U.S. Pat. No. 4,353,463, issued Oct. 12, 1982, to R. W. Seemann, discloses a resin-containing cartridge assembly for applying multi-component curable mixtures to a substrate with at least one curable component disposed in a pressure rupturable container. A liquid-permeable mixer assembly is arranged at one end of the container, with an arrangement for selectively rupturing the container disposed adjacent to the mixer assembly. A nozzle disposed adjacent an exit end of the mixer assembly permits selective discharge of the resulting mixture. A basic disadvantage of these pressure-type of mixing containers is that a suitable mixing action is not always obtained prior to discharge of the mixed components.